Maggie Barcellano sits down for dinner with her daughter, Zoe, 3, at Barcellano's father's house in Austin, Texas. Barcellano enrolled in the food stamps program to help save up for paramedic training.

In a first, working-age people now make up the majority in U.S. households that rely on food stamps - a switch from a few years ago, when children and the elderly were the main recipients.

Some of the change is due to demographics, such as the trend toward having fewer children. But a slow economic recovery with high unemployment, stagnant wages and an increasing gulf between low-wage and high-skill jobs also plays a big role. It suggests that government spending on the $80 billion-a-year food stamp program - twice what it cost five years ago - may not subside significantly anytime soon.

Food stamp participation since 1980 has grown the fastest among workers with some college training, a sign that the safety net has stretched further to cover America's former middle class, according to an analysis of government data by economists at the University of Kentucky. Formally called Supplemental Nutrition Assistance, the program now covers 1 in 7 Americans.

The findings coincide with the latest economic data showing workers' wages and salaries growing at the lowest rate relative to corporate profits in U.S. history.

President Obama's State of the Union address Tuesday night is expected to focus in part on reducing income inequality. Congress, meanwhile, is debating cuts to food stamps, with Republicans including House Majority Leader Eric Cantor of Virginia wanting a $4 billion-a-year reduction to an antipoverty program that they say promotes dependency and abuse.

As recently as 1998, the working-age share of food stamp households was at a low of 44 percent, before the dot-com bust and subsequent recessions in 2001 and 2007 pushed new enrollees into the program, according to the analysis by James Ziliak, director of the Center for Poverty Research at the University of Kentucky.